diff --git a/crane-build.nix b/crane-build.nix
index 4c05d7ec..84b16b21 100644
--- a/crane-build.nix
+++ b/crane-build.nix
@@ -30,7 +30,10 @@ let
 
   args = {
     inherit version;
-    src = ./.;
+    src = lib.fileset.toSource {
+      root = ./.;
+      fileset = lib.fileset.fileFilter ({ hasExt, ... }: !hasExt "nix") ./.;
+    };
     strictDeps = true;
 
     env = {
@@ -71,19 +74,31 @@ let
     // {
       inherit cargoArtifacts;
 
+      outputs = [
+        "out"
+        "dkms"
+      ];
+
+      makeFlags = args.makeFlags ++ [
+        "DKMSDIR=${placeholder "dkms"}"
+      ];
+
       enableParallelBuilding = true;
       buildPhaseCargoCommand = ''
         make ''${enableParallelBuilding:+-j''${NIX_BUILD_CORES}} $makeFlags
       '';
       doNotPostBuildInstallCargoBinaries = true;
+      enableParallelInstalling = true;
       installPhaseCommand = ''
-        make ''${enableParallelBuilding:+-j''${NIX_BUILD_CORES}} $makeFlags install
+        make ''${enableParallelInstalling:+-j''${NIX_BUILD_CORES}} $makeFlags install install_dkms
       '';
 
       doInstallCheck = true;
       nativeInstallCheckInputs = [ versionCheckHook ];
       versionCheckProgramArg = "version";
 
+      passthru.kernelModule = import ./module-build.nix package;
+
       meta = {
         description = "Userspace tools for bcachefs";
         license = lib.licenses.gpl2Only;
diff --git a/flake.nix b/flake.nix
index 8b38ba19..84d3ac31 100644
--- a/flake.nix
+++ b/flake.nix
@@ -42,6 +42,12 @@
     }:
     let
       systems = nixpkgs.lib.filter (s: nixpkgs.lib.hasSuffix "-linux" s) nixpkgs.lib.systems.flakeExposed;
+
+      cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
+      rustfmtToml = builtins.fromTOML (builtins.readFile ./rustfmt.toml);
+
+      rev = self.shortRev or self.dirtyShortRev or (nixpkgs.lib.substring 0 8 self.lastModifiedDate);
+      version = "${cargoToml.package.version}+${rev}";
     in
     flake-parts.lib.mkFlake { inherit inputs; } {
       imports = [ inputs.treefmt-nix.flakeModule ];
@@ -55,6 +61,8 @@
 
       inherit systems;
 
+      flake.overlays.default = import ./overlay.nix { inherit inputs version; };
+
       perSystem =
         {
           self',
@@ -68,12 +76,6 @@
             inherit system;
             overlays = [ (import rust-overlay) ];
           };
-
-          cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
-          rustfmtToml = builtins.fromTOML (builtins.readFile ./rustfmt.toml);
-
-          rev = self.shortRev or self.dirtyShortRev or (lib.substring 0 8 self.lastModifiedDate);
-          version = "${cargoToml.package.version}+${rev}";
         in
         {
           packages =
@@ -84,18 +86,17 @@
                   localSystem = system;
                   pkgs' = import nixpkgs {
                     inherit crossSystem localSystem;
-                    overlays = [ (import rust-overlay) ];
+                    overlays = [
+                      (import rust-overlay)
+                      self.overlays.default
+                    ];
                   };
+
                   withCrossName =
                     set: lib.mapAttrs' (name: value: lib.nameValuePair "${name}-${crossSystem}" value) set;
-
-                  craneBuild = pkgs'.callPackage ./crane-build.nix { inherit crane version; };
-                  crossPackages = {
-                    "bcachefs-tools" = craneBuild.package;
-                    "bcachefs-tools-fuse" = craneBuild.packageFuse;
-                  };
                 in
-                (withCrossName crossPackages) // lib.optionalAttrs (crossSystem == localSystem) crossPackages;
+                (withCrossName pkgs'.bcachefsPackages)
+                // lib.optionalAttrs (crossSystem == localSystem) pkgs'.bcachefsPackages;
               packages = lib.mergeAttrsList (map packagesForSystem systems);
             in
             packages
@@ -109,6 +110,8 @@
               bcachefs-tools-aarch64-linux
               bcachefs-tools-fuse
               bcachefs-tools-fuse-i686-linux
+              bcachefs-module-linux-latest
+              bcachefs-module-linux-testing
               ;
             inherit (pkgs.callPackage ./crane-build.nix { inherit crane version; })
               # cargo-clippy
@@ -127,6 +130,8 @@
                   pname = "${prev.pname}-msrv";
                 }
               );
+
+            nixos-test = pkgs.nixosTest (import ./nixos-test.nix self');
           };
 
           devShells.default = pkgs.mkShell {
diff --git a/module-build.nix b/module-build.nix
new file mode 100644
index 00000000..5d3410d4
--- /dev/null
+++ b/module-build.nix
@@ -0,0 +1,67 @@
+/*
+  Copyright (c) 2003-2025 Eelco Dolstra and the Nixpkgs/NixOS contributors
+
+  Permission is hereby granted, free of charge, to any person obtaining
+  a copy of this software and associated documentation files (the
+  "Software"), to deal in the Software without restriction, including
+  without limitation the rights to use, copy, modify, merge, publish,
+  distribute, sublicense, and/or sell copies of the Software, and to
+  permit persons to whom the Software is furnished to do so, subject to
+  the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+bcachefs-tools:
+{
+  lib,
+  stdenv,
+  kernelModuleMakeFlags,
+  kernel,
+}:
+
+stdenv.mkDerivation {
+  pname = "bcachefs";
+  version = "${kernel.version}-${bcachefs-tools.version}";
+
+  __structuredAttrs = true;
+
+  src = bcachefs-tools.dkms;
+
+  nativeBuildInputs = kernel.moduleBuildDependencies;
+
+  enableParallelBuilding = true;
+
+  makeFlags = kernelModuleMakeFlags ++ [
+    "KDIR=${kernel.dev}/lib/modules/${kernel.modDirVersion}/build"
+    "INSTALL_MOD_PATH=${placeholder "out"}"
+  ];
+
+  installPhase = ''
+    runHook preInstall
+    make -C ${kernel.dev}/lib/modules/${kernel.modDirVersion}/build M=$(pwd) modules_install "''${makeFlags[@]}" "''${installFlags[@]}"
+    runHook postInstall
+  '';
+
+  passthru = {
+    inherit (bcachefs-tools.passthru) tests;
+  };
+
+  meta = {
+    description = "out-of-tree bcachefs kernel module";
+
+    inherit (bcachefs-tools.meta)
+      license
+      maintainers
+      ;
+  };
+}
diff --git a/nixos-test.nix b/nixos-test.nix
new file mode 100644
index 00000000..015c46a5
--- /dev/null
+++ b/nixos-test.nix
@@ -0,0 +1,34 @@
+self': {
+  name = "bcachefs-nixos";
+
+  nodes.machine =
+    { config, ... }:
+    {
+      assertions = [
+        {
+          assertion =
+            config.boot.bcachefs.modulePackage or null == self'.packages.bcachefs-module-linux-latest;
+          message = "Local bcachefs module isn't being used; update nixpkgs?";
+        }
+      ];
+
+      virtualisation.emptyDiskImages = [
+        {
+          size = 4096;
+          driveConfig.deviceExtraOpts.serial = "test-disk";
+        }
+      ];
+
+      boot.supportedFilesystems.bcachefs = true;
+      boot.bcachefs.package = self'.packages.bcachefs-tools;
+    };
+
+  testScript = ''
+    machine.succeed(
+      "modinfo bcachefs | grep updates/src/fs/bcachefs > /dev/null",
+      "mkfs.bcachefs /dev/disk/by-id/virtio-test-disk",
+      "mkdir /mnt",
+      "mount /dev/disk/by-id/virtio-test-disk /mnt",
+    )
+  '';
+}
diff --git a/overlay.nix b/overlay.nix
new file mode 100644
index 00000000..9d9ddd44
--- /dev/null
+++ b/overlay.nix
@@ -0,0 +1,20 @@
+{ inputs, version }:
+final: prev:
+let
+  craneBuild = prev.callPackage ./crane-build.nix {
+    inherit version;
+    inherit (inputs) crane;
+  };
+in
+{
+  bcachefsPackages = {
+    "bcachefs-tools" = craneBuild.package;
+    "bcachefs-tools-fuse" = craneBuild.packageFuse;
+    "bcachefs-module-linux-latest" =
+      final.linuxPackages_latest.callPackage craneBuild.package.kernelModule
+        { };
+    "bcachefs-module-linux-testing" =
+      final.linuxPackages_testing.callPackage craneBuild.package.kernelModule
+        { };
+  };
+}